Beethoven and Bach may be good for your diet. A study carried out by Dr Maria Simonson, director of the health, weight and stress programme at the Johns Hopkins University School of Medicine in the US, discovered people ate less when listening to classical music. The study suggested that lively, fast-paced music encourages people not only to eat more but also to digest food faster. Those who tuned into an upbeat 60s song, for instance, ate about five forkfuls a minute, took 30 minutes to finish their meal and asked for seconds. Those listening to gentle classical music ate three forkfuls a minute and took almost an hour to finish the same lunch.

Day-glo colours

It's no coincidence that fast food cartons often come in garish colours. In a separate study, Simonson discovered that changing the colour of food cartons and cups from orange and yellow to black and white reduced the amount of food sold during coffee breaks in a company cafe. She concluded that warm hues - orange, red, yellow - made food look better and stimulated diners' appetites. "Red, orange and yellow are fast vibration colours," says colour therapist Susan Farrar. "They draw you in and give instant gratification. Sweets and drinks are packaged in red. Manufacturers know it's a motivating colour for both the eyes and taste buds."

Getting married

"We tend to take on the bad eating habits of our partners," says nutritionist Ingrid Haitink. "Along with settling down and eating more 'regular' meals at home, this normally adds up to larger portion sizes." According to a study by Cornell University published in the journal Social Science & Medicine, newlyweds gain more weight on average than singles or people who are divorced. For marriage not to affect your waistline, remember you don't always have to eat the same meal as your partner. Just because one person fancies fried chicken doesn't mean the other can't have it grilled.

Lack of sleep

"Lack of sleep changes blood sugar levels and metabolism. It also affects impulse control: it's harder for people who are fatigued to pass on food they know they shouldn't be eating, purely for the energy fix," says Dr Kingman Strohl of University Hospitals in Cleveland. Being tired creates boredom, lowers your diet defences and you wind up eating for comfort. Dr Pamela Peeke, an assistant professor of medicine at the University of Maryland, says, "90% of the women I see would lose weight if they got a few more hours' sleep a night."

Too much choice

Our bodies' appetite-regulating mechanisms are easily overridden by the sight, taste and smell of food, even when we're not hungry. We are ultimately seduced by quantity ratherthan quality and forget about the calorie content. In a study by scientists at the University of Buffalo, New York, volunteers given a four-course meal with a different food for each course ate 44% more than those served the same food for each of the courses.

Sweet things

"Serotonin plays a key role in controlling our moods," Haitink explains. "The body acknowledges serotonin's calming effect when we reach for the refined carbohydrates in the comforting taste and textures of sweets and starches. These can be looked on as a self-administered dose of brain medication to fight off the blues and regain some balance." This explains why we feel happier after having eaten sweets or sugary drinks. It also explains why we crave them when feeling down. The best way to get your sugar fix is from a more slowly absorbed carbohydrate such as a piece of flapjack, a wholemeal scone or dried fruit.

Stress

Stress eating isn't just emotional, it's also biological. The "stress hormone" cortisol is released in the body during times of angst. "When cortisol is released, it can increase fat storage in the abdominal area," explains nutritionist Judith Wills, author of The Diet Bible (Quadrille). "It seems the deep fat in the stomach contains receptors that the cortisol prefers." An excess of stress also triggers cortisol to boost blood sugar levels which, if not used, are converted by insulin into fat for storage.